The impact of host plant resistance and tillage management on the sugar beet root aphid, Pemphigus betae, and its terrestrial predators

Sugar beet root aphid (SBRA), Pemphigus betae Doane, is a renowned pest of sugar beet in the American Midwest. Control of this insect is complicated by their cryptic life history. In an effort to curb their populations, several sugar beet varieties have been developed that show resistance against SBRA. In 2010, an ongoing study was initiated at Scottsbluff, Nebraska to test for possible SBRA resistance in several sugar beet varieties (Beta66RR50, Beta66RR60, CRR714, HM9042RR, HM9024RR, HM9027RR, HM4093RR) under differing tillage conditions (till vs. zone-tilling). Concurrent to this, the first year of an extensive pitfall study was established to test for differences in the abundance of potential soil-dwelling arthropod predators at different aphid infestation levels (no infest, low-, medium-, and high infest) between the different sugar beet varieties and tillage practices. Preliminary results from this study indicated differences in the degree of SBRA resistance between the tested sugar beet varieties. This was evident with the sugar beet variety, HM9042RR, which harbored more aphids in the plowed plots compared to the zone tilled plots. As expected, more sugar to molasses was lost at higher SBRA infestation levels, whilst top weight was also affected by aphid infestation levels. Additionally, overall pounds of sugar are decreased under aphid infestation. Preliminary pitfall results revealed some potential SBRA arthropod predators on account of their high occurrence. These included Opiliones, Araneae, Chilopoda, Staphylinidae and Carabidae (possibly including Cicindelinae).